Which gas is released during the prep stage of cellular respiration?

Which gas is released during the prep stage of cellular respiration?

• A. Oxygen
• B. Methane
• C. Nitrogen
• D. Carbon dioxide

Answer: (D)

During cellular respiration, the preparatory stage (pyruvate oxidation) releases carbon dioxide. In this step, each pyruvate produced from glycolysis enters the mitochondrion and is decarboxylated, losing a carbon as CO2 and becoming an acetyl group that binds CoA to form acetyl-CoA. This reaction also reduces NAD+ to NADH. Oxygen isn’t produced here; it’s used later in the electron transport chain as the final electron acceptor. Nitrogen and methane aren’t involv­ed in this pathway. So carbon dioxide is the gas released during the prep stage.

During cellular respiration, the preparatory stage (pyruvate oxidation) releases carbon dioxide. In this step, each pyruvate produced from glycolysis enters the mitochondrion and is decarboxylated, losing a carbon as CO2 and becoming an acetyl group that binds CoA to form acetyl-CoA. This reaction also reduces NAD+ to NADH. Oxygen isn’t produced here; it’s used later in the electron transport chain as the final electron acceptor. Nitrogen and methane aren’t involv­ed in this pathway. So carbon dioxide is the gas released during the prep stage.